Electrolyte replenishment fluids are a beneficial factor for patients undergoing preparation for colonoscopy. This poses a problem in that most oral rehydration solutions rely on glucose for co-transportation of electrolytes across the brush border of the small bowel utilizing the GLUT1 transport mechanism. Sugars however are known to cause fermentation and production of combustible gases, unacceptable in colonoscopy where the use of electro-cautery during polypectomy may lead to intracolonic explosion.
Due to these concerns there has been an increasing emphasis on maintaining fluid and electrolyte homeostasis in the patient and avoidance of sugars. The challenge for developing safe and effective bowel preparations has thus been to deliver a product that is: tolerable due to acceptable taste and low volume of the preparation; safe by maintaining electrolyte balance and fluid homeostasis; and, able to minimize side effects and lead to better patient acceptance and compliance in consuming the purgative to better clean the bowel.
Several issues have become apparent with the use of conventional sugars used in some current purgatives. In particular, the recorded cases of intra-colonic combustion/explosion secondary to fermentation of the sugars by colon bacteria is a potential problem, although no instances of such complications actually occurred using the described preparations. There were three factors which could contribute to a potential explosion during colonoscopy. These include the remaining colonic bacterial load, propensity of the sugar to produce fermentation products such as methane and hydrogen, and the use of an electro-cautery during colonoscopy. This complication remains a feared but at most but a theoretical problem since only very small quantities of sugar have been incorporated into the purgative compositions described in the past. There is, nevertheless, continuing perception that some non-absorbable sugars such as mannitol or lactulose—may still, potentially pose an explosive potential. In spite of the addition of electrolytes and the addition of such sugars, the side-effect profile—and while much more favorable thane before—still included occasional patients who experienced headaches, suggesting a need for an improved electrolyte delivery system.
In some products, minimally degradable carbohydrates (sugars) are added to the lavage composition to facilitate the physiological balance of coupled 1:1 transport of sodium and glucose in the small intestine so as to reduce electrolyte loss and concomitant fluid shifts. These carbohydrates also have the ability to provide added purgative effect.